So I've done some more digging, Googling and testing ...
I cannot find the OpenChange log, or it's not obvious. But I extracted these from ocsmanager.log
2014-07-30 12:19:16,321 ERROR [ocsmanager.lib.config] [MainThread] /etc/ocsmanager/ocsmanager.ini: Missing [autodiscover:rpcproxy] section
Removing PID file /var/run/ocsmanager/ocsmanager.pid
From SOGo, every time I try to set the Out of Office, I get the following:
Jul 30 11:49:37 sogod [5257]: [ERROR] <0x0x7f5c444117a8[NGLdapAttribute]> could not convert value of objectSid to string
Jul 30 11:49:37 sogod [5257]: [ERROR] <0x0x7f5c44411208[NGLdapAttribute]> could not convert value of objectGUID to string
It's the best I've been able to find thus far, I've spent days trawling through the logs looking for errors.